1. Field of the Invention
The present invention relates to a technical field of a network controlling apparatus, a connection mode controlling apparatus, a network controlling method, a connection mode controlling method, a network controlling program, and a connection mode controlling program. More specifically, the invention relates to a technical field of a network controlling apparatus, a connection mode controlling apparatus, a network controlling method, a connection mode controlling method, a network controlling program, and a connection mode controlling program for controlling a distribution mode of distributing distribution information distributed from a distribution source in a network system while stepwisely relaying the distribution information in a relay unit which is connected while constructing a hierarchy of a plurality of levels.
2. Discussion of the Related Art
In recent years, as the speed of the Internet lines for houses increases, a network system is being commonly used. In the network system, a network is constructed by connecting personal computers and the like in houses in a tree structure whose apex is a single distributing apparatus as a distribution source, and so-called contents such as music and movies is distributed as distribution information from the distributing apparatus via the network. The network is called “topology” from the viewpoint of the connection mode. Each of the distributing apparatus and the personal computers constructing the network is generally called a “node”.
For example, Patent Document 1 discloses a conventional technique of the network system.    Patent Document 1: Japanese Patent Laid-Open No. 2003-169089
In each of nodes included in a conventional network system typified by the network system of Japanese Patent Laid-Open No. 2003-169089, contents transferred from a upper-order node is temporarily stored in a buffer memory and provided for a reproducing process and the like. The configuration is intended to reduce the influence of fluctuations in transfer speed in the Internet circuit constructing a distribution path in the network system. As the buffer memory, for example, an FIFO (First In First Out) memory such as a ring buffer memory is used.
On the other hand, in the network system, the nodes constructing the system are personal computers and the like in houses as described above. Consequently, there may be a case such that the power of any of the nodes on the distribution path is turned off irrespective of whether contents is being distributed or not. In such a case, the function of relaying the contents to lower-order nodes connected to the node whose power switch is turned off stops.
In the case where the relaying function stops in any of the nodes on the distribution path during distribution of contents in the network system, the topology is reconstructed so as to include the nodes other than the node in which the relay function stops (that is, the distribution path from the distributing apparatus to the lower-order nodes directly connected to the node whose relay function stops is reconstructed and distribution is restarted).